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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bernard Zhao <bernard@vivo.com>,
        Paul Moore <paul@paul-moore.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0335/1039] selinux: fix potential memleak in selinux_add_opt()
Date:   Mon, 24 Jan 2022 19:35:24 +0100
Message-Id: <20220124184136.568570374@linuxfoundation.org>
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From: Bernard Zhao <bernard@vivo.com>

[ Upstream commit 2e08df3c7c4e4e74e3dd5104c100f0bf6288aaa8 ]

This patch try to fix potential memleak in error branch.

Fixes: ba6418623385 ("selinux: new helper - selinux_add_opt()")
Signed-off-by: Bernard Zhao <bernard@vivo.com>
[PM: tweak the subject line, add Fixes tag]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/selinux/hooks.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index dde4ecc0cd186..49b4f59db35e7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -988,18 +988,22 @@ out:
 static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 {
 	struct selinux_mnt_opts *opts = *mnt_opts;
+	bool is_alloc_opts = false;
 
 	if (token == Opt_seclabel)	/* eaten and completely ignored */
 		return 0;
 
+	if (!s)
+		return -ENOMEM;
+
 	if (!opts) {
 		opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
 		if (!opts)
 			return -ENOMEM;
 		*mnt_opts = opts;
+		is_alloc_opts = true;
 	}
-	if (!s)
-		return -ENOMEM;
+
 	switch (token) {
 	case Opt_context:
 		if (opts->context || opts->defcontext)
@@ -1024,6 +1028,10 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 	}
 	return 0;
 Einval:
+	if (is_alloc_opts) {
+		kfree(opts);
+		*mnt_opts = NULL;
+	}
 	pr_warn(SEL_MOUNT_FAIL_MSG);
 	return -EINVAL;
 }
-- 
2.34.1